Abstract: At the present,boat mounted anti-collision device appears in two kinds.The first one equipped with radar has the disadvantage of high cost,difficulty in integrated management and deployment.The second one is GPS receiver which is cheap but weak in collision.Therefore,boat mounted anti-collision device based on GPS+GPRS is put forward.By the device,systematic mode and de-drifting arithmetic are used in watching center to calculate the collision possibility of two or more active boats.Boat mounted anti-collision device based on GPS+GPRS with lower cost is a perfect integration of two traditional anti-collision devices.